Apparatus for shedding in weaving looms

ABSTRACT

A shedding apparatus for a weaving loom has the warp threads thereof connected to corresponding electrical conductors located in a transverse magnetic field. Current is selectively directed to the conductors so that they selectively displace their associated warp threads to form a shed.

United States Patent [191 Doehler et al.

[ June 18, 1974 1 1 APPARATUS FOR SI-IEDDING IN WEAVING LOOMS [76]Inventors: Peter Doehler, Kaulbachstrasse 59; Erich Rudolf Baumgartner,Tiroler Platz 4, both of Munich, Germany [22] Filed: Apr. 18, 1972 [21]Appl. No.: 245,143

[30] Foreign Application Priority Data Apr. 20, 1971 Germany 2119053[52] US. Cl 139/55, 139/317, 139/319 [51] Int. Cl D03c13/00, D03c 19/00[58] Field of Search 139/55, 59, 317, 319;

[56] References Cited UNlTED STATES PATENTS 983,862 2/1911 Regal 139/3191,881,076 10/1932 Haebler 139/319 X 2,204,891 6/1940 Hamilton 139/553,103,953 9/1963 Lauri'tsen t 139/55 3,114,398 12/1963 Pfarrwaller139/134 X FOREIGN PATENTS OR APPLICATIONS 901,396

1/1954 Germany 139/319 Primary Examiner-James Kee Chi Attorney, Agent,or FirmGriffin, Branigan & Butler ABSTRACT A shedding apparatus for aweaving loom has the warp threads thereof connected to correspondingelectrical conductors located in a transverse magnetic field. Current isselectively directed to the conductors so that they selectively displacetheir associated warp threads to form a shed.

28 Claims, 9 Drawing Figures PAIENTEDJummn 3.817292 SHEET 1 [IF 4PATENTEDM 18 I974 SHEET 2 0F 4 FIG. 3

23 WTFTFWTW I I APPARATUS FOR SHEDDING IN WEAVING LOOMS FIELD OF THEINVENTION This invention relates to means for shedding at weaving loomsof any type.

BACKGROUND OF THE INVENTION It is known that, for shedding, there areused heddles which are provided with ears or loops and which are raisedand lowered for forming a shed of the warp threads either united ingroups, together with each other and in one andthe same directionby ashaft machine, or selectively individually by means of the Jacquardmachine.

In the case in which the heddles are individually moved, theaccommodation of the individual drive elements in as small a space aspossible meets with difficulties especially in the case of greatdensities of the warp threads. That is why one has already arranged theindividual heddles staggered in'longitudinal direction of the warpthreads to be thereby able to enlarge the distance between the driveelements for the heddle to permit the accommodation of the structuralelements required.

It is furthermore disadvantageous that known shedding means, due to thenecessity of providing a-common drive source for all heddles, have agreat inertia which'permits fulfilling of a control command only atrestricted speed and thus limits the weaving velocity.

The object of the invention is to solve the problem of reducing theinertia of the driving means for moving the individual warp threads aswell as the space requirement for the requisite drive elements.

SUMMARY OF THE INVENTION.

This problem is solved in that with each warp thread or with each groupof warp threads to be always actuated in one and the same direction andsimultaneously there is coupled at least one conductor which is feedableselectively with electrical current and which extends transversely ofthe intended direction of deflection of the threads, and in thatfor eachrespective group of these conductors or for all of these conductorsthere is provided a magnet which produces a magnetic field extendingsubstantially transversely of the longitudinal direction of theconductors and transversely of the intended direction of deflection ofthe threads. Preferably the individual conductors arelocated parallel tothe longitudinal direction of the warp threads, while for each warpthread to be moved there may be provided a plurality of conductorsconnected in series with respect to each other.

In this case, the series connected parallel conductors constitute part'of a flat coil one of the coil sides of which cooperates with themagnets field when current is fed to the conductors. The opposite coilside opposes the magnets field and functions to limit the coils motionto a predetermined amount. In this manner, the

opposite coil side provides an electromagnetic abutment, so to speak.

According to a further advantageous embodiment of the invention, theindividual flat coils may be arranged on a coil carrier consisting ofmagnetizable material so that a stack of coil carriers almost bridgesover the space between the magnetic poles of the magnet and thusdecreases the magnetic resistance of the magnetic circuit of this magnetand achieves induction values adequate for individual coil movement.

The connections to the individual conductors or to the coils can beproduced according to methods which are known per se from the printedcircuit art so that the individual conductors or coils can be arrangedextremely closely adjacent each other and corresponding densities ofwarp threads can be achieved.

To all embodiments of the invention it is common that a driving force isproduced for a predetermined warp thread in that an associated conductorlocated in amagnetic field has applied to it a voltage for producing apredetermined direction of current in this conductor corresponding to acontrol command so that this conductor undergoes a deflection in a knownmanner, the direction of which can be determined for example accordingtothe right hand screw rule from one conductor to another. The deflectionis transmitted either directly or by way of coupling. elements to an earor loop or to a groove which imparts a corresponding movement to theassociated warp thread. The driving force which acts on the individualwarp threads and which must be adjusted to the tension of the warpthread is proportional to the intensity of the magnetic field, to thecurrent intensity, eventually to the number of conductors used for eachwarp thread and fed with current, as well as'to the length of theseconductors in the magnetic field. Hence by varying these parameters, itis possible to achieve a suitable driving force even though one of theseparameters, for example the intensity of the magnetic field, is notdeliberately variable.

Useful embodiments of the invention are subject matter of the attachedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be elucidatedin greater detail in the light of a number of illustrative embodimentswith reference to the attached drawings, in which FIG. 1 shows aschematical perspective view of an apparatus according to the invention,

FIG. 2 shows a sectional schematical side view of another embodiment ofthe apparatus according to the invention, i

FIG. 3 is a perspective schematical view of a further.

embodiment of the invention,

FIGS..3a, 3b and 3c show partial schematical views of details of theapparatus according to FIG. 3,

FIG. 4 is a 'greatly simplified sectional side view of an embodimentwhich is a modification of that according to FIG. 1,

FIG. 5 is a side view of an additional device utilizable in conjunctionwith the embodiment according to FIG. 3, and

FIG. 6 is an embodiment which is a modification of that according toFIG. 3 and which is shown in a greatly simplified mode ofrepresentation.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION In FIG. 1 are showna few warp threads 1 to 6 guided through ears or loops 7. Whereas theears associated with the warp threads 1, 2 and 3 are lowered so far thatthese warp threads extend substantially in straight lines, the ears 7associated with the warp threads 4, S and 6 are raised so far that thelast-mentioned warp threads together with the warp threads 1, 2i and 3define a high shed into which the shuttle indicated schematically at 8can be shot. The warp beam,goods piece beam and the reed are omitted inthe drawing for the sake of simplicity.

The ears 7 are coupled via heddles or rods 9 to current conductors 10which are each associated therewith and which are tensioned between agrounded busbar 11 and terminals 12 selectively connectable by way ofpairs of switches13 and 14 respectively to a busbar of negative voltageor to a busbar of a positive voltage 15 or 16 respectively.

The current conductors 10 extend along a substantial length portion oftheir total length between the busbar 11 and the terminals 12 within anintense magnetic field which is produced by the pole shoes 17 and 18 ofa magnet as shown schematically in FIG. 1, and which is orientedsubstantially transversely of the longitudinal extension of the currentconductors 10 as well as transversely of the intended direction ofdeflection of these current conductors.

When there is a small distance between the pole shoes 17 and 18 forexample for making narrow ribbons by using a limited number ofconductors 10 arranged side by side, the magnet can comprise a permanentmagnet. When there are greater distances between the pole shoes 17 and18, then an electromagnet is suitably used, which may carry asuperconductive exciter winding for achieving high intensities of themagnetic field.

The terminals 12, the switch pairs 13 and 14 as well as the busbars l5and 16 can be arranged on a printed circuit board, and as switches 13and 14 there may be preferably used electronic semiconductor switchelements which may be provided in an array where they are spaced in anydesired spacing on the printed circuit so that the individual currentconductors 10 can be placed adjacent each other in any correspondingspaced relationship apart from each other.

In order to avoid twisting or entanglement between the warp threads orbetween the current conductors l0 by reason of their closely adjacentarrangement, it can be advantageous in accordance with the embodimentshown in FIG. 4 to connect each of the current conductors 10 by way of asail-like or wafer-like plate 19 with the associated ear 7 so that theindividual wafers or plates 19 located parallel to each other ensure aguide for the current conductors l0 and also for the warp threads 7during the upward and downward movement of the current conductors 10.According to an embodiment which is not shown here, for this purposeeach plate or wafter 19 can be also lengthened underneath the ear 7 sothat the ear 7 is enclosed by an associated plate 19 or constitutes partof this plate.

FIG. 3 shows an embodiment wherein the current conductors selectivelyconnectable to voltage constitute a coil 20 the coil side 21 of whichformed of a plurality of current conductors extending parallel to eachother upon connection via switch means 22 to a voltage source 23cooperates with the magnetic field existing between the magnet poles l7and 18 in the sense of a lifting of the coil 20 concerned.

The coils 20 are mounted by an etching technique or by a pressingtechnique onto coil carriers 24 which consist of thin wafers ofsynthetic material or of thin plates of a magrietizable material.

As shown in FIG. 3a, the coils 20 disposed on the coil carrier 24 can becovered with an insulating layer 25 which has excellent slidingcharacteristics and which consists for example of tetrafluoroethylene.When the coil carriers 24 are made of magnetizable material, for exampleof a ferrite, then the additional advantage is achieved that nearly thewhole air interspace between the pole shoes 17 and 18 is filled up witha material of higher permeability so that the magnetic resistance of theclosing circuit can be decreased and the effective field intensity foreach coil 20 can be enhanced.

In the structure according to FIG. 3b, the coil carrier 24 consists alsoof a ferromagnetic plate, while a surrounding layer 25' consists of anepoxy resin which is mixed with ferrite and which can be applied by thedip-' ping method, spraying method or by vortex sintering, and intowhich the individual conductors of the coil 20 have been embedded inthat after application of the conductive paths these paths are pressedinto the layer 25' or covered with a second layer of epoxy resin mixedwith ferrite. The advantage of this structure resides in that also thespaces filled with insulating material between the plates 24 have greatpermeability since the epoxy resin mixed with ferrite has a highelectrical resistance but low magnetic resistance.

According to the modified embodiment in FIG. 3c, the ferromagnetic plate24 is replaced by a fiberglass mat 24' which is embedded into ferriteepoxy resin.

As shown in the schematic view in FIG. 3, the individual coils 20 areconnected via springy or resilient connecting lines with the switchmeans 22 and with the grounded busbar 11 respectively. For the sake ofsimplicity of the representation, a cassette-like or troughlike guideframe for the lateral support and guidance of the stack formed of thecoils 20 is omitted. Should the sliding properties of the coil carrier24 or of the coil cover 25 respectively be insufficient to achieve areliable lifting of an individual coil 20 or of the associated coilcarrier 24 respectively from the entire coil stack by using the producedelectromagnetic driving forces, then on the guide frame there can beadditionally provided also a means 40 for blowing-in of air into thecoil stack whereby the frictional forces between the individual coilsare practically eliminated. Similar means can be provided also for theembodiment according to FIG. 6 further described hereinbelow.

In corresponding manner like in the embodiment according to FIG. 1, theears 7 are connected to the bottom portion to the coil carriers 24 byrods or heddles 9.

In the embodiment according to FIG. 1 as well as in that according toFIG. 3, however, the arrangement can be such that the warp threads runabove the individual current conductors 10 and above the coils 20respectively.

For the embodiment according to FIG. l, such a modification is shown inFIG. 2. The ears 7 in this embodiment are placed directly adjacent thetop side of the current conductors 10 having the shape of bows whichextend between the grounded busbar l 1 and the terminals 12 and whichundergo a bending downwardly or upwardly according to the actuation ofthe switches 13 and 14 in the sense of a connection with the busbars 15or 16.

According to a very important further development of the invention, theswitch means for connection of the current conductors 10 and of thecoils 20 respectively are designed so that they permit a shortpulse-like current impingement of the conductors and coils respectively.The same applies to a device according to the invention in which theswitch means are placed in their desired positions and held there duringthe working stroke which is then generated by a pulse-like current tothe conductors and coils to which the switches are connected.

Such a short-time current impingement has the advantage that thepermissible current intensities can be extraordinarily great withoutexceeding a maximum permissible thermal limit to achieve correspondinglygreat actuating forces, even though short-timed, bistable and tristableholding means can be provided in order to' maintain the individual warpthread in its actuated position for a duration sufficient for insertingthe shuttle despite the shorttime switching-in of the electromagneticdrive such embodiments of the invention the short, great actuating forceof the electromagnetic drive for the respective warp causes the holdingmeans to change from one state into the other and then remain in thisnew state until the electromagnetic drive means is operated in theopposite sense. It is to be noted only in passing here that in such acase, in the embodiment according to FIG. 3, in place of the simpleswitch means 22 there should be provided the respective switch pairs 13and 14 for connection with busbars of different polarity l5 and 16,respectively.

The bistable or tristable holding means can be a suitable mechanical,electromagnetic or magnetic means. Examples of magnetically effectivebistable holding means are small magnet blocks or shoes secured alongthe upper edge of the coil carrier 24 and cooperating with a strip offerromagnetic material extending above the coils in the transversedirection, or again a magnetic strip which cooperates with the coilcarriers 24 made of magnetizable material so that an individual coil orits coil carrier 24 respectively is fixed-by the magnetic forces in theraised position until a current impingement in the opposite sense of therespective coil takesplace. I

An example of mechanically effective tristable holding means is givenpurely schematically in FIG. 5. Two

sector-shaped plates 26 and 27 are urged apart from each other by aspring 28 and against respective associated (surfaces of engagement) 29'and 30 respectively. The coil carrier 24 is coupled via arms 31 to thesectors 26 and 27 with respect to the vertical movements and can assume,in accordance with the cooperation of the sectors 26 and 27 with theengagement surfaces 29 and 30, respectively, three stable positionswhich can be changed by short-timed current feeding of the coil 20 ofthe coil carrier 24. Of course, in place of the coil carrier 24 also asingle current conductor 10 can be connected via arms 31 the top of FIG.5.

The short-timed current impingement of the conductors or coilsrespectively while simultaneously using bistable or tristable holdingmeans has the further advantage that the current impingement can becarried out in a rapid time sequence progressively, by a switch controldevice (41 FIG. 3). For example, from one conductor to another and fromone coil to another respectively transversely of the longitudinaldirection of the warp threads so that the shed is formed "likewiseprogressively in the transverse direction. In this manner, it ispossible to carry out the actuation of the warp threads and theexcitation of the electromagnetic drive means associated therewithrespectively with a limited to the means shown in The embodimentaccording to FIG. 6 shows that the individual coils 20 when connected tovoltage must not necessarily perform a translatory motion but can justas well perform a pivotal mo vemenLTo this end, the coil carrier 24consisting of resilient material may be pivoted about a film fulcrumjoint 32 over which also the supply lines for the coil 20 are passed ina flexible form. The stack of coils arranged adjacent each other is heldby means of a clamping device 33 behind which are located the terminals34 which are only schematically indicated in FIG. 6 and which lead tothe switch means 13 and 14. According to a practical embodiment whichhowever is not shown in detail in the drawings, a printed circuit board42 is directly connected behind the clamping device 33. 4

While the apparatus according to the invention is not limited toparticular weaving methods or particular dimensions of the woven fabricto be produced, the advantages of the invention are clearly shown in theexample for making ribbons.

.What is claimed is:

1. Apparatus for forming a shed in the warp threads of a weaving loomcomprising:

means for forming a magnetic field in a designated location; at leastone electrical conductor in said location separate from said means forforming a magnetic field;

means for bodily connecting said electrical conductor to a correspondingwarp thread; and,

means for selectively directing current to said electrical conductor tocause motion of said conductor and saidwarp thread bodily connectedthereto.

2. Apparatus according to claim 1 wherein a plurality of electricalconductors is provided, each of said conductors being-bodily connectedwith a corresponding one of said warp threads and being selectivelyfeedable with electric current.

3. Apparatus according to claim 1 wherein a plurality of electricalconductors is provide-d, each of said con ductors being bodily connectedwith a corresponding group of warp threads to be always actuatedsimultaneously and in one and the same direction.

4. Apparatus according to claim 1 wherein a plurality of groups ofelectrical conductors are provided each of said groups of conductorsbeing bodily connected corresponding one of said warp threads and beingselectively feedable with electric current.

5. Apparatus according to claim 1 wherein said at least one conductorextends parallel to the longitudinal direction of the corresponding warpthread.

6. Apparatus according to claim 4 wherein said electrical conductors ofeach group of conductors are arranged parallel to each other and areconnected in series.

7. Apparatus according to calim 6 wherein said electrical conductors ofeach group of conductors are forming part of a flat coil.

8. Apparatus according to claim 7 wherein said conductors forming partof a flat coil are arranged on a thin plate shaped coil carrier.

9. Apparatusaccording to claim 8 wherein said conductors are applied tosaid coil carrier by being impressed therein.

. 10. Apparatus according to claim 8 wherein said conductors are appliedto said coil carrier by an etching technique.

1 1. Apparatus according to claim 8 wherein said coil carrier consistsat least partially of magnetizable material.

12. Apparatus according to claim 8 wherein means are provided forblowing a gas stream into the interspaces between the coil carriers.

13. Apparatus according to claim 8 wherein at least one of the surfacesof the coils and the coil carriers respectively is covered with amaterial of good sliding characteristics.

14. Apparatus according to claim 1 comprising holding means forselectively holding each electrical conductor in first or secondpositions and further comprising switch means for feeding current pulsesto the conductors.

15. Apparatus according to claim 14 wherein said switch means areadapted for progressive control of the current feeding to each conductorin a time sequence in the direction of the breadth of the woven fabric.

16. Apparatus according to claim 14 wherein said holding means aremechanical means comprising a spring loaded snap actuating mechanism.

17. Apparatus according to claim 14 wherein said holding means aremagnetic.

18. Apparatus according to claim 14 wherein said holding means areelectromagnetic.

19. Apparatus according to claim 1 wherein each warp thread runs abovethe corresponding conductor in a groove or ear secured to the respectiveconductor.

20. Apparatus according to claim l'wherein each warp thread runsunderneath the corresponding conductor in an ear secured to therespective conductor.

- 21 Apparatus according to claim 1 wherein flexible current supplylines connect said at least one conductor to printed circuit meansextending across the breadth of the woven fabric.

22. Apparatus according to claim 7, wherein said flat coil is arrangedon a coil carrier which is pivotable about a pivot point.

23. Apparatus according to claim 8, wherein at least one of the surfacesof the coils and the coil carriers, respectively is covered with a highpermeability insulating material.

24. Apparatus according to claim 1 wherein aluglike guide plate issecured to each conductor said luglike guide plate extending parallel tothe longitudinal direction of the respective conductor.

25. The apparatus of claim 13 wherein said material is comprised oftetrafluoroethylene.

26. The apparatus of claim 14 wherein said holding means is bistable.

27. The apparatus of claim 14 wherein said holding means is tristable.

'28. The apparatus ofclaim 23 wherein said high permeability insulatingmaterial is a ferrite epoxy resin.

1. Apparatus for forming a shed in the warp threads of a weaving loomcomprising: means for forming a magnetic field in a designated location;at least one electrical conductor in said location separate from saidmeans for forming a magnetic field; means for bodily connecting saidelectrical conductor to a corresponding warp thread; and, means forselectively directing current to said electrical conductor to causemotion of said conductor and said warp thread bodily connected thereto.2. Apparatus according to claim 1 wherein a plurality of electricalconductors is provided, each of said conductors being bodily connectedwith a corresponding one of said warp threads and being selectivelyfeedable with electric current.
 3. Apparatus according to claim 1wherein a plurality of electrical conductors is provided, each of saidconductors being bodily connected with a corresponding group of warpthrEads to be always actuated simultaneously and in one and the samedirection.
 4. Apparatus according to claim 1 wherein a plurality ofgroups of electrical conductors are provided each of said groups ofconductors being bodily connected corresponding one of said warp threadsand being selectively feedable with electric current.
 5. Apparatusaccording to claim 1 wherein said at least one conductor extendsparallel to the longitudinal direction of the corresponding warp thread.6. Apparatus according to claim 4 wherein said electrical conductors ofeach group of conductors are arranged parallel to each other and areconnected in series.
 7. Apparatus according to calim 6 wherein saidelectrical conductors of each group of conductors are forming part of aflat coil.
 8. Apparatus according to claim 7 wherein said conductorsforming part of a flat coil are arranged on a thin plate shaped coilcarrier.
 9. Apparatus according to claim 8 wherein said conductors areapplied to said coil carrier by being impressed therein.
 10. Apparatusaccording to claim 8 wherein said conductors are applied to said coilcarrier by an etching technique.
 11. Apparatus according to claim 8wherein said coil carrier consists at least partially of magnetizablematerial.
 12. Apparatus according to claim 8 wherein means are providedfor blowing a gas stream into the interspaces between the coil carriers.13. Apparatus according to claim 8 wherein at least one of the surfacesof the coils and the coil carriers respectively is covered with amaterial of good sliding characteristics.
 14. Apparatus according toclaim 1 comprising holding means for selectively holding each electricalconductor in first or second positions and further comprising switchmeans for feeding current pulses to the conductors.
 15. Apparatusaccording to claim 14 wherein said switch means are adapted forprogressive control of the current feeding to each conductor in a timesequence in the direction of the breadth of the woven fabric. 16.Apparatus according to claim 14 wherein said holding means aremechanical means comprising a spring loaded snap actuating mechanism.17. Apparatus according to claim 14 wherein said holding means aremagnetic.
 18. Apparatus according to claim 14 wherein said holding meansare electromagnetic.
 19. Apparatus according to claim 1 wherein eachwarp thread runs above the corresponding conductor in a groove or earsecured to the respective conductor.
 20. Apparatus according to claim 1wherein each warp thread runs underneath the corresponding conductor inan ear secured to the respective conductor. 21 Apparatus according toclaim 1 wherein flexible current supply lines connect said at least oneconductor to printed circuit means extending across the breadth of thewoven fabric.
 22. Apparatus according to claim 7, wherein said flat coilis arranged on a coil carrier which is pivotable about a pivot point.23. Apparatus according to claim 8, wherein at least one of the surfacesof the coils and the coil carriers, respectively is covered with a highpermeability insulating material.
 24. Apparatus according to claim 1wherein a lug-like guide plate is secured to each conductor said lug-like guide plate extending parallel to the longitudinal direction of therespective conductor.
 25. The apparatus of claim 13 wherein saidmaterial is comprised of tetrafluoroethylene.
 26. The apparatus of claim14 wherein said holding means is bistable.
 27. The apparatus of claim 14wherein said holding means is tristable.
 28. The apparatus of claim 23wherein said high permeability insulating material is a ferrite epoxyresin.